The invention relates to metal detectors and, more particularly, to a detector that detects ferrous magnetic metal objects and generates a signal indicating the presence of the ferrous objects.
In a restaurant, many times eating utensils, such as silverware or stainless steel flatware, are accidentally thrown away and discarded unknowingly into the trash, thus costing many hundreds of dollars in loss. The problem results from the restaurant employees inadvertently tossing the silverware or flatware into the garbage while cleaning food and other waste from the restaurant's clientele's used plates.
Some restaurant kitchens use automatic means for rinsing and removing food and garbage from the plates. Also, food scrapers may be used to clean debris from the plates. The eating utensils may be inadvertently disposed of without the kitchen help being aware of the problem.
A flatware recover food scraper is disclosed in U.S. Pat. No. 4,367,138 to Kustas and includes a cylindrically shaped rubber food scraper mounted to a table over a refuse container, which is located below the table. Food and waste is scraped from the dishes and the stainless steel flatware is attracted to and held by magnets located within the scraper.
U.S. Pat. No. 4,494,657 to Oldenkamp discloses an integral housing member for removing magnetic articles from a flow of loosely packed material. The housing includes a magnetic article assembly which attracts and removes magnetic articles responsive to the magnetic field from a loosely packed material flow which is directed through the housing.
U.S. Pat. No. 4,279,744 to Antonwitsch discloses an apparatus for removing magnetic articles from a flow of loosely packed material. The apparatus includes an elongated shaft attached to a plurality of magnetic members for attracting, removing, and holding the magnetic articles.
However, these devices which attract and remove magnetic articles may miss silverware or flatware which is wrapped within napkins or positioned behind other non-magnetic articles. These devices do not detect the presence of eating utensils or signal a person that the eating utensil is being thrown away. Therefore, if the device does not actually attract and remove the eating utensil, then the eating utensil remains in the garbage.
U.S. Pat. No. 6,833,789 to Carmen discloses a detector having a coil detect the presence of magnetized ferrous metal objects. However, Carmen uses an oscillator to generate a voltage on the coil, which requires FCC approval. Additionally, Carmen does not use a non-ferrous core, the use of which would enhance the detection of the metal object.
U.S. Pat. No. 5,001,425 to Beling discloses a detector using a pair of detection coils and an oscillator. Beling does not use a non-ferrous core.
U.S. Application 2002/0067163 to Goldberg discloses a detector having two separate non-ferrous cores, having a coil wound about the outside surface of each solid core. The object passes between the two cores, but not through the cores, reducing the dependability of the detector.
Therefore, what is needed is an apparatus for detecting ferrous metal eating utensils that eliminates the inadvertent disposal of the eating utensils into garbage cans by utilizing a pick-up coil wound about a non-ferrous core that generates a voltage when a magnetized object passes through the coil and signals, either audibly and/or visually, a person that the eating utensil has been thrown into the garbage can. A person can then retrieve the eating utensil from the garbage.